Cold temperatures can make surface instabilities linger longer than usual. Be cautious as you transition into wind-affected terrain.
Watch for signs of slab formation in the surface snow, particularly in areas loaded by north winds and where buried surface hoar could be preserved (think sheltered openings at mid elevations).
Recent storm snow covers a crust and isolated surface hoar which has produced natural, remote and rider-trigger avalanches. Investigate this interface. As the fresh snow settles and gains cohesion, a reactive upper snowpack may form.
On Friday, continued reports of natural and remotely triggered avalanches to size 2.5 in the alpine and treeline . On Wednesday and Thursday an avalanche cycle up to size 2.5 was reported, including remotely triggered avalanches to size 2. Many of the avalanches ran on surface hoar buried on Jan 4. A few size 1-2 wind slabs 30-60 cm deep were triggered by rider traffic, these occurred on east-to-north aspects above 2200 m.
Roughly 40-60 cm of new snow fell in the region early this week. It buried a mix of crusts, surface hoar, and facets. Areas where surface hoar may be preserved are of greatest concern.
A crust formed by early December rain is found ~70 cm deep, and an old layer of surface hoar 60-100 cm deep. Recent observations suggest triggering this layer is unlikely. The lower snowpack is variable throughout the region and weak basal facets are likely to be found on the ground in shallow snowpack areas.
Saturday night
Partly cloudy. Northwest alpine wind, 10-40 km/h. Treeline temperature -28 °C.
Sunday
Partly cloudy with possible flurries. Northwest alpine wind 20-50 km/h. Treeline temperature -22 °C.
Monday
Mostly sunny. Northwest alpine wind 10-50 km/h. Treeline temperature -20 °C.
Tuesday
Mix of sun and cloud with possible flurries. Southwest alpine wind 10-30 km/h. Treeline temperature -18 °C.
More details can be found in the Mountain Weather Forecast.
